Samit Chattopadhyay

Prof. Samit Chattopadhyay

Director, CSIR – Indian Institute of Chemical Biology

FTWAS, FNA, FASc, FNASc; J C Bose National Fellow

  • Introduction

    The eukaryotic interphase chromatin is a highly organized structure. Specific scaffolding proteins form complexes with DNA and play pivotal role in DNA packaging. An important feature of DNA packaging involves folding of the chromatin into loop domains, which are periodically attached to the nuclear matrix through binding to specialized DNA sequences called Matrix Attachment Region or MARs. We study how proteins that specifically bind to MARs regulate genomic DNA organization and nuclear biochemical functions such as transcription, recombination, splicing, repair etc. Past several years our lab has been engaged in understanding the role of nuclear matrix and associated proteins in pathophysiological processes. We have focused on one such novel matrix associated protein SMAR1 that is down regulated in human breast cancer. It acts as a global repressor for many genes including Cyclin D1, IkBa and CK8 by directly recruiting HDAC1-mSin3a dependent repressor complex. Our findings reveal that SMAR1 functions in two different ways to regulate global gene expression. First, it acts as a transcriptional repressor and second, it modulates the transactivation potential of transcriptional co-activators NF-kB and p53. Additionally, NF-kB and p53 regulate various transcription factors involved in oncogenic transformation. These cofactors globally affect various signaling pathways leading to activation of genes that onset the process of tumorigenesis. We are therefore focusing our research work on understanding global gene regulation by SMAR1.

    Topics of Research

    • Gene regulation and chromatin remodelling in cancer stem cells
    • Th1-Th2 differentiation of T cells
    • Regulation of splicing through nuclear matrix binding proteins
    • Epigenetic regulation during HIV transcription
    • Molecular mechanisms of DNA damage-repai

    Current Projects

    Role of SMAR1 in Cancer

    Past several years our lab has been engaged in understanding the role of nuclear matrix binding proteins and their association with chromatin modifying complexes in pathophysiological and disease conditions. We have now characterized SMAR1 as a tumor suppressor by virtue of its ability to interact with tumor suppressor p53. We have also shown that SMAR1 delays tumor progression in mouse melanoma model by imposing cell cycle arrest. Additionally, we showed that the tumor suppressor function of SMAR1 resides within the RS domain that interacts with phosphorylated p53 and stabilizes it in the nucleus. Recently we have also shown that Cyclin D1 is a direct transcriptional target of SMAR1 and that SMAR1 is drastically reduced in breast cancer cell lines as well as in various grades of breast carcinoma tissues. SMAR1 regulates the cancer cell proliferation, and metastasis. We also find that chemotherapeutic agents like Doxorubicin induce the expression of SMAR1 in p53 dependent manner. We propose that SMAR1 acts as key regulator of cellular proliferation and metastasis in breast cancer by interplaying between p53 and TGFb pathway.

    Role of SMAR1 in modulating cell cycle arrest and apoptosis

    How tumor suppressor p53 bifurcates cell cycle arrest and apoptosis and executes these distinct pathways is not clearly understood. We find BAX and PUMA promoters harbor an identical MAR element and are transcriptional targets of SMAR1. Upon mild DNA damage, SMAR1 selectively represses BAX and PUMA through binding to the MAR independently of inducing p53 deacetylation through HDAC1. This generates an anti-apoptotic response leading to cell cycle arrest. Conversely, apoptotic DNA damage results in increased size and number of PML nuclear bodies with consequent sequestration of SMAR1. This facilitates p53 acetylation and restricts SMAR1 binding to BAX and PUMA MAR leading to apoptosis. Thus, our study establishes MAR as a damage responsive cis element and SMAR1-PML crosstalk as a switch that modulates the decision between cell cycle arrest and apoptosis in response to DNA damage. [EMBO,2009]

    Regulation of NF-kB mediated transactivation by SMAR1

    Regulation of NF-kB activity constitutes an important parameter for maintaining cellular homeostasis. Aberrant NF-kB activity as is seen in advanced grades of many tumors promotes the secretion of various cytokines and chemokines that help tumor cells to escape immunosurveillance and facilitate metastasis and angiogenesis. Therefore, inhibiting NF-kB activity is a major challenge to curb tumor growth. We have identified a distinct mechanism of NF-kB regulation by SMAR1 where we show that chemotherapeutic agents like Doxorubicin inhibit NF-kB mediated transactivation through SMAR1. The preliminary data suggest that SMAR1 can control specific subset of NF-kB target genes which promotes cancer growth, metastasis and angiogenesis.

    Regulatory function of SMAR1 during IR induced DNA damage in cancer cells

    Preliminary studies from lab suggest that SMAR1 is responsive to various stress stimuli. Therefore identification of stress responsive nature of this protein and delineating the signaling pathway that specifically stimulates the functions of this protein is of paramount importance. Utility of specific post-translational modifiers allows temporal and spatial control over protein relocalization and interactions, and may represent a means for trans-regulatory activation of protein activities. The ability to recognize these specific modifiers also underscores the capacity for signal amplification, a crucial step for the maintenance of genomic stability and tumor prevention. In context with the stress response, we identified a novel ATM phosphorylation site on SMAR1 that mediates an increased association of SMAR1 with Cyclin D1 promoter. The dual effect of SMAR1 i.e. induction of p21 through p53 activation and downregulation of Cyclin D1 by recruitment of corepressor complex causes cell cycle arrest.  SMAR1 is induced in response to any genotoxic insult. The studies are ongoing to decipher the roles of SMAR1 upon DNA damage and repair.

    SMAR1 Represses HIV-1 LTR mediated transcription through chromatin remodeling

    Nuclear Matrix and Matrix Attachment Regions (MARs) have been implicated in the transcriptional regulation of host as well as viral genes but their precise role in HIV-1 transcription remains unclear. Here, we show that >98% of HIV sequences in GenBank contain a consensus MAR element in their 5′ LTRs. We further define the role of this MAR in determining the state of viral transcription and show by MAR-binding assays that the transcriptionally silent HIV LTR has a strong propensity to bind to nuclear matrix. The MAR-binding protein SMAR1 aids in tethering LTR-MAR to nuclear matrix thereby enforcing transcriptional silencing. We have also characterized the minimal DNA sequence in the LTR-MAR to which SMAR1 binds and recruits the HDAC1/Sin3A corepressor complex thereby repressing LTR-mediated transcription (Virology, 2010)

    Role of SMAR1 in T helper (TH) cell differentiation

    The development and function of the T lymphocyte lineage are regulated tightly by signaling pathways that involve lineage-restricted cell surface receptors, intracellular signaling molecules and nuclear transcription factors. Naive T helper cells differentiate into two subsets, TH1 and TH2, each with distinct functions and their respective cytokine profiles. We have earlier shown that SMAR1 down regulates TH1 specific transcription factor T-bet thereby effecting TH1 lineage commitment of T cells. Using SMAR1 transgenic and knockout model we are trying to understand this differentiation process in detail.

    1. Bhagat PN, Jadhav SH, Chattopadhyay S, Paknikar KM. (2018) Carbon nanospheres mediated nuclear delivery of SMAR1 protein (DNA binding domain) controls breast tumor in mice model Nanomedicine. doi: 10.2217/nnm-2017-0298.
    2. Mirlekar B, Gautam D, Chattopadhyay S. (2017) Chromatin Remodeling Protein SMAR1 Is a Critical Regulator of T Helper Cell Differentiation and Inflammatory Diseases. Frontiers in Immunology. 2017 Feb 9;8:72. doi: 10.3389/fimmu. 2017.00072. eCollection 2017.
    3. Patel S, Choksi A, Pant R, Alam A and Chattopadhyay S. (2017) Nutritional programming of metabolic syndrome: Role of nutrients in shaping the epigenetics. A Handbook of nutrition, diet and epigenetics. Springer International Publishing AG 2017. DOI 10.1007/978-3-319-31143-2_42-1
    4. Paul D, Ghorai S., Chattopadhyay S., Dinesh US, Shetty P and Santra MK (2017) Cdc20 directs proteasome-mediated degradation of the tumor suppressor SMAR1 in higher grades of cancer through the anaphase promoting complex. Cell Death and Disease, NPG, In press.
    5. Sengupta P, Chattopadhyay S, Chatterjee S., (2017) G-Quadruplex surveillance in BCL-2 gene: a promising therapeutic intervention in cancer treatment. Drug Discovery 2017 May 12. pii: S1359-6446(17)30245-3. doi: 10.1016/j.drudis.2017.05.001.
    6. Chatterjee B, Banoth B, Mukherjee T, Taye N, Vijayaragavan B, Chattopadhyay S, Gomes J, Basak S. (2016) Delayed IBa synthesis insulates TLR4 induced canonical RelA/NFkB pathway from non-canonical LTbR signaling in myelomonocytic cells. Science Signaling, AAAS, 2016 Dec 6;9 (457): ra120.
    7. Ramu V, Aute S, Taye N, Guha R, Walker MG, Mogare D, Parulekar A, Thomas JA, Chattopadhyay S and Das A. (2017) Photo-induced cytotoxicity and anti-metastaticactivity of ruthenium(II)–polypyridyl complexesQ1 functionalized with tyrosine or tryptophan. Dalton Transaction. 2017 May 5. doi: 10.1039/c7dt00670e. [Epub ahead of print]
    8. Agarwalla H, Mahajan PS, Sahu D, Taye N, Bishwajit Ganguly B, Mhaske SB, Chattopadhyay S, Das A. (2016) A Switch-On NIR Probe for Specific Detection of Hg2+ Ion in Aqueous Medium and in Mitochondria. Inorganic Chemistry.
    9. Anila HA, Ali F, Kushwaha SA, Taye N, Chattopadhyay S, Das A. (2016) A Cysteine Specific Fluorescent Switch for Monitoring Oxidative Stress and Quantification of Aminoacylase-1 in Blood Serum. Analytical Chemistry. 2016 Dec 20; 88 (24): 12161-12168. doi: 10.1021/acs.analchem.6b03066.
    10. Mathai J, Mittal SP, Alam A, Ranade P, Mogare D, Patel S, Saxena S, Ghorai S, Kulkarni AP, and Chattopadhyay S. (2016) SMAR1 binds to T(C/G) repeat and inhibits tumor progression by regulating miR-371-373 cluster. Scientific Reports (NPG) 2016 Sep 27;6:33779. doi: 10.1038/srep33779. PMID: 27671416.
    11. Chemmannur SV, Bhagat P, Mirlekar B, Paknikar KM and Chattopadhyay S. (2016) Carbon nanospheres mediated delivery of nuclear matrix protein SMAR1 to direct experimental autoimmune encephalomyelitis in mice. International Journal of Nanomedicine (12;11:2039-51. doi: 10.2147/IJN.S93571.
    12. Pal S, Ramu V, Taye N, Mogare DG, Yeware AM, Sarkar D, Reddy DS, Chattopadhyay S, Das A. (2016) GSH Induced Controlled Release of Levofloxacin from a Purpose-Built Prodrug: Luminescence Response for Probing the Drug Release in Escherichia coli and Staphylococcus aureus. Bioconjugate Chemistry. 21;27(9):2062-70. doi: 10.1021/acs.bioconjchem.6b00324. Epub 2016 Aug 26.
    13. Mirlekar B, Majumdar S, Khetmalas Mand, Chattopadhyay S (2015) Regulation of T cell lineage commitment by SMAR1 during inflammatory & autoimmune diseases. Indian J Med Res 142, October 2015, pp 405-413.

    14. Reddy G U, A AH, Ali F, Taye N, Chattopadhyay S and Das A (2015) FRET-Based Probe for Monitoring pH Changes in Lipid-Dense Region of Hct116 Cells.Organic Letters, 2015 Nov 2. [Epub ahead of print]

    15. Padhye P, Alam A, Ghorai S, Chattopadhyay S andPoddar P (2015) Doxorubicin-conjugated β-NaYF4:Gd3+/Tb3+ multifunctional, phosphor nanorods: a multi-modal, luminescent, magnetic probe for simultaneous optical and magnetic resonance imaging and an excellent pH-triggered anti-cancer drug delivery nanovehicle.Nanoscale. 2015 Nov 5. [Epub ahead of print]

    16. Ali F, A AH, Taye N, Gonnade RG, Chattopadhyay S, Das A (2015) A fluorescent probe for specific detection of cysteine in the lipid dense region of cells.Chemical Communications (Camb).2015 Oct 7. [Epub ahead of print]

    17. Ali F, Saha S, Maity A, Taye N, Si MK, Suresh E, Ganguly B, Chattopadhyay S, Das A. (2015) Specific Reagent for Cr(III): Imaging Cellular Uptake of Cr(III) in Hct116 Cells and Theoretical Rationalization. Journal of Physical Chemistry B. 2015 Sep 21.[Epub ahead of print].

    18. A AH, G UR, Ali F, Taye N, Chattopadhyay S, Das A (2015) A reagent for specific recognition of cysteine in aqueous buffer and in natural milk: imaging studies, enzymatic reaction and analysis of whey protein.Chemical Communications (Camb).2015 Sep 10.[Epub ahead of print].

    19. Nakka KK, Chaudhary N, Joshi S, Bhat J, Singh K, Chatterjee S, Malhotra R, De A, Santra MK, Dilworth J and Chattopadhyay S. (2015) Nuclear matrix-associated protein SMAR1 regulates alternative splicing via HDAC6-mediated deacetylation of Sam68. Proceedings of National Academy of Sciences, USA 112 (26): E3374- 83. doi: 10.1073/pnas.1418603112. Epub 2015 Jun 15.

    20. Mirlekar B., Ghorai S., Khetmalas M., Bopanna R and Chattopadhyay S. (2015) Nuclear Matrix Protein SMAR1 control regulatory T cell fate during Inflammatory Bowel Disease (IBD). Mucosal Immunology (NPG) , In Press.

    21. Chemmannur SV, Badhwar AJ, Mirlekar B, Malonia SK., Gupta M, Wadhwa N, Bopanna R, Mabalirajan U, Majumdar S, Ghosh B and Chattopadhyay S (2015) Nuclear matrix binding protein SMAR1 regulates T cell differentiation and allergic airway disease. Mucosal Imunology , (NPG),2015 Mar 4. doi: 10.1038/mi.2015.11. [Epub ahead of print]

    22. Khan D, Katoch A, Das A, Sharathchandra A, Lal R, Roy P, Das S, Chattopadhyay S and Das S (2015) Reversible induction of translational isoforms of p53 in glucose-deprivation. Cell Death and Differentiation, (NPG), 015 Feb 27. doi: 10.1038/cdd.2014.220. [Epub ahead of print]

    23. Mirlekar B, Patil S, Bopanna R and Chattopadhyay S. (2015) MAR binding protein SMAR1 favors IL-10 mediated regulatory T cell function in acute colitis. Biochemical and Biophysical Research Communication, In Press.

    24. Khan D., Chattopadhyay S. and Das S. (2015) Influence of metabolic stress on translation of p53 isoforms. Molecular and Cellular Oncology, In Press.

    25. Yadav B, Malonia SK, Majumdar SS, Gupta P, Wadhwa N, Badhwar A, Gupta UD, Katoch VM and Chattopadhyay S (2015) Constitutive expression of SMAR1 confers susceptibility to Mycobacterium tuberculosis infection in a transgenic mice model. Indian Journal of Medical Research , (In press).

    26. Reddy U G, Firoj Ali, Taye N, Chattopadhyay S and Das A (2015). A new turn on Pd2+-specific fluorescence probe and its use as an Imaging reagent for cellular uptake in Hct116 cells. Chemical Communications, (Cambridge) 2015 Feb 12;51(17):3649-52. doi: 10.1039/c4cc10171e.

    27. Chaudhary N, Nakka K K, Pavithra L, Bhat J, Chatterjee S and Chattopadhyay S (2014) SMAR1 coordinates HDAC6-induced deacetylation of Ku70 and dictates cell fate upon irradiation. Cell Death and Disease, (NPG), 2014 Oct 9, e1447; doi: 10.1038

    28. Malonia SK., Yadav B, Sinha S, Lazennec G and Chattopadhyay S (2014) Chromatin remodeling protein SMAR1 regulates NF-kB dependent Interleukin-8 (IL-8) transcription in breast cancer. The International Journal of Biochemistry & Cell Biology, 2014 Sep 18; 55C:220-226. doi: 10.1016/j.biocel.2014.09.008. [Epub ahead of print]

    29. Mirlekar B, Majumdar S, Khetmalas M and Chattopadhyay S (2014) Regulation of T cell lineage commitment by SMAR1 during Inflammatory and Autoimmune Diseases. Indian Journal of Medical Research, In Press.

    30. Reddy G U. , Ramu V., Roy S., Taye N., Chattopadhyay S. and Das A. (2014)Specific probe for Hg2+ to delineate even H+ in pure aqueous buffer / Hct116 colon cancer cells: Hg(II)-?2-arene p-interaction and a TBET-based fluorescence response. Chemical Communications, (Cambridge), 2014 Oct 23; 50(92):14421-4. doi: 10.1039/c4cc06740a.

    31. Chemmannur S and Chattopadhyay S (2014) Role of nuclear matrix associated region (MAR) binding proteins in the regulation of T helper cell differentiation. Proceedings of Indian National Science Academy, June 2 issue, 2014.

    32. G UR, Agarwalla H, Taye N, Ghorai S, Chattopadhyay S, Das A. (2014) A novel fluorescence probe for estimation of Cysteine/ Histidine in human blood plasma and recognition of endogenous Cysteine in live Hct116 cells. Chemical Communications Cambridge 2014 Jul 31;50(69):9899-902. doi: 10.1039/c4cc04214j

    33. Patel S, Choksi A and Chattopadhyay S (2014) Understanding Inter-individual Epigenetic Variations in Obesity and its Management. Personalized Epigenetics, Book chapter, Elsevier publication (In Press).

    34. Adhikary A, Chakraborty S, Mazumdar M, Ghosh S, Mukherjee S, Manna A, Mohanty S, Nakka KK, Joshi S, De A, Chattopadhyay S, Sa G, Das T. (2014)Inhibition of Epithelial to Mesenchymal transition by E-cadherin up-regulation via repression of Slug transcription and inhibition of E-cadherin degradation: Dual role of SMAR1 in breast cancer cells. Journal of Biological Chemistry, Jul 30. 2014 Aug 1. pii: jbc.M113.527267. [Epub ahead of print]

    35. Chakraborty S, Das K, Saha S, Mazumdar M, Manna A, Chakraborty S, Mukherjee S, Khan P, Adhikary A, Mohanty S, Chattopadhyay S, Biswas S, Sa G,Das T. (2014) Nuclear matrix protein SMAR1 represses c-Fos-mediated HPV18 E6 transcription through alteration of chromatin histone de-acetylation.Journal of Biological Chemistry, Journal of Biological Chemistry 2014. Aug 25. pii: jbc.M114.564872. [Epub ahead of print]

    36. Dhar A., Mallick S., Maiti A., Ghosh P.; Ahmed, I., Bhattacharyya S., Mandal T., Manna A., Singh S., Nayak D., Wilder, P., Markowitz, J., Weber D., Ghosh M., Chattopadhyay S., Guha, R., Konar A., Bandyopadhyay S. and Roy S. (2014) Simultaneous inhibition of key growth pathways in melanoma cells and tumor regression by a designed bidentate constrained helical peptide.Biopolymers. 101 (4): 344-358.

    37. Chakraborty S, Adhikary A, Mazumdar M, Mukherjee S, Bhattacharjee P, Guha D. Choudhuri T, Chattopadhyay S, Sa G, Sen A and Das T, (2014) Capsaicin-induced activation of p53-SMAR1 auto-regulatory loop down-regulates VEGF in non-small cell lung cancer to restrain angiogenesis. PLoS ONE, 13; 9 (6), 1-11.

    38. Mittal S P., Kulkarni A. P., Mathai J., Chattopadhyay S. and Pal J. K. (2014) Dose-dependent differential response of mammalian cells to cytoplasmic stress is mediated through the heme-regulated eIF2a kinase. International Journal of Biochemistry and Cell Biology 2014 Jul 31;54C:186-197. doi: 10.1016/j.biocel.2014.07.016.

    39. Mittal S. P, Mathai J, Kulkarni A P, Pal J. K. and Chattopadhyay S. (2013) miR-320a regulates erythroid differentiation through MAR binding protein SMAR1. International Journal of Biochemistry and Cell Biology, 45 (11):2519-2529.

    40. Singh S, Raina V, Chavali P L, Dubash T, Kadreppa S, Parab P, Chattopadhyay S. (2012) Regulation of GAD65 expression by SMAR1 and p53 upon Streptozotocin treatment. BMC Molecular Biology September issue 14; 13 : 28

    41. Chaudhary N., Nakka K K., Maulik N. and Chattopadhyay S., (2012) Epigenetic manifestation of metabolic syndrome and dietary management, Antioxidants & Redox Signaling,Jul 15;17 (2):254-81. Epub 2012 Mar 2

    42. Sinha S, Malonia SK, Mittal P K S, Pal J K and Chattopadhyay S. (2012) Chromatin remodelling protein SMAR1 inhibits p53 dependent transactivation by regulating acetyl transferase p300. International Journal of Biochemistry and Cell Biology , 44 (1): 46-52.

    43. Sen GS, Mohanty S, Hossain DM, Bhattacharyya S, Banerjee S, Chakraborty J, Saha S, Ray P, Bhattacharjee P, Mandal D, Bhattacharya A, Chattopadhyay S, Das T and Sa G. (2011) Curcumin enhances the efficacy of chemotherapy by tailoring p65 NFkB-p300 cross-talk in favor of p53-p300 in breast cancer. Journal of Biological Chemistry, 2011 Dec 9; 286 (49): 42232-47. Epub 2011 Oct 19.

    44. Malonia SK., SinhaS., Pavithra L., Singh K., Jalota-Badhwar A., Rampalli S.,Kaul-Ghanekar R. and Chattopadhyay S.,(2011) Generegulation by SMAR1: Role in cellular homeostasis and cancer, BBA Reviews on Cancer, 2011 Jan; 1815(1): 1-12 (IF:12).

    45. Pavithra L, Chavali S. and Chattopadhyay S. (2010) Nutritional epigenetics- impact on metabolic syndrome. Review in book chapter on Molecular Mechanisms of Epigenetics. CRC Press. (2010), In Press.

    46. Chattopadhay, S. Protein decides arrest or death. Nature News , doi:10.1038/ nindia.(2010).65; Published online, May 2010

    47. Kopikar S., Choudhari A S., Kumari A., Chattopadhyay S. and Kaul-Ghanekar R. (2010), Aqueous cinnamon extract (ACE-c) from the bark of Cinnamomum cassia causes apoptosis in human cervical cancer cell line (SiHa) through loss of mitochondrial membrane potential. BMC Cancer, May 18; 10: 210.

    48. Sreenath K., Pavithra L., Singh S, Sinha S, Raut S, Dash PK., Siddappa NB., Mangaiarkarasi A, Ranga UK, Mitra D. andChattopadhyay S. (2010)  Nuclear Matrix Protein SMAR1 Represses HIV-1 LTR Mediated Transcription through Chromatin Remodeling. Virology, 25; 400(1):76-85.

    49. Sinha S, Malonia SK, Mittal SPK, Singh K, Kadreppa S, Kamat R., Mukhopadhyaya R., Pal JK and  Chattopadhyay S. (2010) Coordinated regulation of p53 apoptotic targets BAX and PUMA by SMAR1 through an identical MAR element, EMBO Journal. 29, 830-842.

    50. Pavithra L., Sreenath K., Singh S. and Chattopadhyay S,. (2010) Heat shock protein 70 binds to a novel sequence in 5′ UTR of tumor suppressor SMAR1 and regulates its mRNA stability upon PGA2 treatment. FEBS Letters, 19; 584(6): 1187-92.

    51. Singh S, Sreenath K, Pavithra L, Roy S, Chattopadhyay S. (2010), SMAR1 regulates free radical stress through modulation of AKR1a4 enzyme activity. International Journal of Biochemistry and Cell Biology. 42 (7): 1105-14.

    52. Singh K., Sinha S, Malonia SK and Chattopadhyay S., (2010) Tumor Necrosis Factor alpha (TNFalpha) regulates CD40 expression through SMAR1 phosphorylation. Biochemical and Biophysical Research Communication. 2010 8; 391(2): 1255-61

    53. Nakka K. and Chattopadhyay, S. (2009) Modulation of chromatin by MARs and MAR binding oncogenic transcription factor SMAR1. Molecular and Cellular Biochemistry, 336(1-2):75-84

    54. Kaul-Ghanekar R., Singh S., Mamgain H., Jalota-Badhwar A., Paknikar K. M. and Chattopadhyay S. (2009) SMAR1, a phenotypic diagnostic marker for differentiation between cancerous and non-cancerous cells: combined AFM and SEM study. BMC Cancer,Oct 2; 9:350.

    55. Pavithra L., Mukherjee S. Kadreppa S., Kar S., Sakaguchi K.,  Roy S. and Chattopadhyay S., (2009) SMAR1 forms ternary complex with p53-MDM2 and negatively regulates p53 mediated transcription. Journal of Molecular Biology, 388(4):691-702.

    56. Singh V B, Pavithra L, Chattopadhyay S, Pal JK., (2009)Stress-induced overexpression of the heme-regulated eIF-2alpha kinase is regulated by Elk-1 activated through ERK pathway.Biochemical and Biophysical Research Communication. 2009 379(3): 710-5.

    57. Singh K, Sinha S, Malonia SK, Bist P, Tergaonkar V, Chattopadhyay S.(2009)Tumor suppressor SMAR1 represses IkBa expression and inhibits p65 transactivation through MARs. Journal of Biological Chemistry, 9; 284 (2):1267-78.

    58. Pavithra L, Singh S, Sreenath K, Chattopadhyay S. (2009) Tumor suppressor SMAR1 downregulates Cytokeratin 8 expression by displacing p53 from its cognate site. International Journal of Biochemistry and Cell Biology. 41(4):862-71.

    59. Bavikar SN, Salunke DB,Hazra BG, Pore VS, Dodd RH, Thierry J, Shirazi F, Deshpande MV, Kadreppa S, Chattopadhyay S. (2008), Synthesis of chimeric tetrapeptide-linked cholic acid derivatives: impending synergistic agents. Bioorganic & Medicinal Chemistry Letters, 18 (20):5512-7.

    60. Vatmurge NS, Hazra BG, Pore VS, Shirazi F, Deshpande MV, Kadreppa S, Chattopadhyay S, Gonnade RG. Synthesis and biological evaluation of bile acid dimers linked with 1, 2, 3-triazole and bis-beta-lactam. Organic and Biomolecular Chemistry. 2008, Oct 21; 6(20):3823-30.

    61. Pavithra L, Rampalli S, Sinha S., Sreenath K., Pestell R. G. and Chattopadhyay S. (2007) Stabilization of SMAR1 mRNA by PGA2 involves a stem loop structure in the 5′ UTR. Nucleic Acids Research, 35:6004-6016.

    62. Singh, K. Mogare, D. Ramprasad O. G., Rajinikanth G., Pande, G. and Chattopadhyay, S. (2007) p53 Target Gene SMAR1 is dysregulated in Breast Cancer: Its Role in Cancer Cell Migration and Invasion.PLoS-ONE, 2(8): e660.

    63. Pavithra,L and Chattopadhyay, S. (2007) Chromatin and cancer: Reprogramming chaos in the cell. Natl. Acad. Sci. 30 (3&4), 71-82.

    64. Jalota-Badhwar,A., Kaul-Ghanekar, R., Mogare, D., Boppana, R., Packnikar, K. M. and Chattopadhyay, S.(2007) SMAR1-derived P44 peptide retains its tumor suppressor function through modulation of p53. Journal of Biological Chemistry, 282(13): 9902-13.

    65. Chattopadhyay S and Pavithra L. MARs and MARBPs: key modulators of gene regulation and disease manifestation. Chromatin and Disease: Book, Vol 41, Series: Subcellular Biochemistry,Edited by Kundu and Dasgupta, Springer, 2006.

    66. Sarkar A, Kulkarni A, Chattopadhyay S, Mogare D, Sharma KK, Singh K, Pal JK. Lead-induced upregulation of the heme-regulated eukaryotic initiation factor 2alpha kinase is compromised by hemin in human K562 cells.Biochim Biophys Acta. 2005Dec 30; 1732(1-3):15-22. Epub 2005.

    67. Rampalli,S., Pavithra, L., Bhatt A., Tapas K. Kundu and Chattopadhyay, S. Tumor suppressor SMAR1 mediates Cyclin D1 repression by recruitment of SIN3/HDAC1 complex. Molecular and Cellular Biology,2005. Vol. 25 October

    68. Jalota A, Singh K, Pavithra L, Kaul R, Jameel S, Chattopadhyay S. (2005) Tumor suppressor SMAR1 activates and stabilizes p53 through its arginine-serine (RS) rich motif. Journal of Biological Chemistry, 280 (16), 16019-16029.

    69. Kaul-Ghanekar,R., Majumdar, S., Jalota, A., Gulati, N., Dubey, N., Saha, B., Chattopadhyay, S. (2005) Abnormal V(D)J Recombination of T Cell Receptor {beta} Locus in SMAR1 Transgenic Mice. Journal of Biological Chemistry, 280 (10): 9450-9459.

    70. Kulkarni, A, Ravi, D. S., Singh, K., Rampalli, S., Parekh, V., Mitra, D., Chattopadhyay, S. (2005) HIV-1 Tat modulates T-bet expression and induces Th1 type of immune response Biochemical and Biophysical Research Communication. 329 (2): 706-712.

    71. Kaul-Ghanekar, R., Jalota, A., L. Pavithra, Tucker, P. and Chattopadhyay, S. (2004) SMAR1 and Cux/CDP modulate chromatin and act as negative regulators of the TCRb enhancer (Eb). Nucleic Acids Research, 32; 16: 4862-4875.

    72. Kulkarni, A., Pavithra L, Rampalli, S., Mogare, D., Babu, K. Shiekh, G., Ghosh, S. and Chattopadhyay, S. (2004) HIV-1 integration sites are flanked by potential MARs that alone can act as promoters. Biochemical and Biophysical Research Communication, 322; 7672-77.

    73. Rampalli, S., Kulkarni, A., Kumar, P., Mogare D., Galande, S., Mitra, D and Chattopadhyay, S. (2003) Stimulation of Tat independent transcriptional processivity from the HIV-1 LTR promoter by Matrix Attachment Regions. Nucleic Acids Research, 31, 3248-3256.

    74. S. Chattopadhyay (2003) Anticancer protein identified, September issue 2003, Nature News, London,

    75. Kaul, R., Mukherjee, S., Ahmed, F., Bhat, M. K., Chhipa, R., Galande, S. and Chattopadhyay, S. (2003) Direct interaction and activation of p53 by SMAR1 causes cell cycle arrest at G2/M phase and delays tumor growth in mice. International Journal of Cancer, 103 (5), 606-615 (Cover page picture from our lab).

    76. Prasad, D. V., Parekh, V. V., Banerjee, P. P., Chattopadhyay, S., Kumar, A. and Mishra, G. C. (2002) the Th1-specific costimulatory molecule, m150, is a post-translational isoform of lysozyme-associated membrane protein-1. Journal of Immunology, 169 (4); 1801-9.

    77. Sarkar, A., Chattopadhyay, S., Kaul, R. and Pal, J. K. (2002) Lead exposure and heat shock inhibit cell proliferation in human HeLa and K562 cells by inducing expression and activity of the heme-regulated eIF-2-aKinase. Journal of Biochemistry, Molecular Biology & Biophysics, 6, 391-396.

    78. Chattopadhyay S., Kaul R., Charest A., Houseman, D. and Chen, J.  SMAR1, a novel alternatively spliced gene product, binds to scaffold/ matrix associated region at TCRb locus.  Genomics, 68, 93. 2000.

    79. Whitehurst, C., Chattopadhyay, S. and Chen, J.(1999) Control of V(D)J recombinational accessibility of the Db1 gene segment at the TCRb locus by a germline promoter.  Immunity, 10, 1-20.

    80. Chattopadhyay, S., Whitehurst, C., E. and Chen, J. (1998)A nuclear matrix attachment region (MAR) upstream of the T cell receptor gene enhancer binds Cux/ CDP and SATB1 and functions to repress transcription. Journal of Biological Chemistry, 45, 29838-29846.

    81. CChattopadhyay, S., Whitehurst, C., E., Schwenk, F. and Chen, J.  (1998) Biochemical and functional analysis of chromatin changes of the T cell receptor ?gene locus during CD4-CD8- to CD4+CD8+ thymocyte differentiation.  Journal of Immunology, 160, 1256-1267.

    82. Das, A., Pal, M., Garcia, M. J., Crossley, R., Whalen, W., Wolska, K., Byrd, R. A., Court, D., Costantino, N., Mazzula, M., Rees, W., von Hippel, P., Chattopadhyay, S., DeVito, J. and Ghosh, B., (1996) Components of a multiprotein-RNA complex that controls transcription elongation in E. coli phage lambda.  Methods in Enzymology, 274: pp 374-402.

    83. Chattopadhyay, S., Hung, S. C., Das, A and Gottesman. M. E. (1995) Interaction between the phage HK022 Nun protein and the nut RNA of phage lambda. PNAS, USA, 92:   pp12131-12135.

    84. Chattopadhyay,S., Garcia, M.J. and Das, A. (1995) Bipartite function of a small RNA hairpin in transcription antitermination in bacteriophage lambda. PNAS, USA, 92: 4061-4065.

    85. Chattopadhyay, S.,Garcia, J., Lazinski, D. and Das, A.(1991) Molecular basis of nut site recognition.  Journal of Cellular Biochemistry, 15: 246.

    86. Nair,B., Oku,Y., Takeda,Y., Ghosh, A., Ghosh, R.K., Chattopadhyay, S., Pal, S. C., Kaper, B.J., Takeda, T. (1988) Toxin profiles of vibrio cholerae  Non-01 from environmental sources in Calcutta, India. Applied and Environmental Microbiology, 54: 3180.

    87. Chattopadhyay, S. and Ghosh, R.K. (1988) Characterization of the transfer RNA coded by Vibrio eltor phage e4.  Virology, 165: 606.

    88. Chattopadhyay, S. and Ghosh, R.K. (1988) Localization of the transfer RNA gene on the physical map of Vibrio eltor  phage e4. Virology,162: 337.

    89. Chattopadhyay, S., Kinchington, D. and Ghosh, R.K. (1987) Characterization of Vibrio eltor typing phages: Properties of the eltor phage e4. J. Gen.Virology, 68: 1411-1416.